Colorectal cancer (CRC) is the third most common cause of cancer and cancer death in the USA. Despite the availability of evidence-based screening and prevention methods for CRC, rates of screening adherence have been suboptimal. Most behavioral interventions designed to increase CRC screening (CRCS) have had limited success. Interventions based on a theoretical model such as Leventhal's Self-Regulation Model (or Common-Sense Model of Illness Representations) that incorporates both the cognitive and emotional influences on behavior may be more effective for promoting cancer screening behaviors. Understanding illness representations (i.e., cause, control, timeline, consequences, identity, coherence, emotional) is particularly valuable because it identifies targets for interventions to restructure disease-related beliefs, which then would lead to more favorable health behaviors and disease outcomes. It also may increase receptivity to specific messages, thereby improving the effectiveness of health communication-based interventions. Few studies have examined illness representations for disease threats or health risks among healthy individuals, as we propose in the current study. Additionally, among the few studies that have examined illness risk representations, different measures are used and not all domains are assessed in every study, which highlights the need for standard, validated measures of illness risk representations among healthy persons. The Revised Illness Perceptions Questionnaire (IPQ-R) has been adapted for numerous diseases and conditions and used with diagnosed and healthy individuals, but not CRC or CRC risk. Critiques of the IPQ-R suggest that simple adaptations will produce imprecise measures and fail to capture disease-specific beliefs; therefore, we extended the IPQ-R to include additional items and subscales based on our formative work and reviews of the literature. The objective of the study is to produce a novel validated instrument to measure illness representations of CRC risk. We will accomplish this with a large cross-sectional survey to address the following specific aims: Aim 1) Determine the factor structure (number of domains) of the new IPQ-R adapted for CRC risk; Aim 2) Determine the measurement equivalence of the new IPQ-R adapted for CRC risk across specific subgroups defined by gender, race, diabetes status, and CRCS status; and Aim 3) Examine the construct validity and additional correlates of the new IPQ-R adapted for CRC risk. The new instrument will be an important resource for researchers for identifying new avenues for improving intervention research to increase CRCS and other cancer prevention behaviors which would then reduce CRC morbidity and mortality.